Page last updated: 2024-12-04

selenocysteine

Description Research Excerpts Clinical Trials Roles Classes Pathways Study Profile Bioassays Related Drugs Related Conditions Protein Interactions Research Growth

Description

Selenocysteine: A naturally occurring amino acid in both eukaryotic and prokaryotic organisms. It is found in tRNAs and in the catalytic site of some enzymes. The genes for glutathione peroxidase and formate dehydrogenase contain the TGA codon, which codes for this amino acid. [Medical Subject Headings (MeSH), National Library of Medicine, extracted Dec-2023]

selenocysteine : An alpha-amino acid that consists of alanine where one of the methyl hydrogens is substituted with a seleno group. [Chemical Entities of Biological Interest (ChEBI), Hastings J, Owen G, Dekker A, Ennis M, Kale N, Muthukrishnan V, Turner S, Swainston N, Mendes P, Steinbeck C. (2016). ChEBI in 2016: Improved services and an expanding collection of metabolites. Nucleic Acids Res]

FloraRankFlora DefinitionFamilyFamily Definition
CodongenusA set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).[MeSH]BoraginaceaeThe Borage plant family is in the class Magnoliopsida, subclass Asteridae, order Lamiales. It is characterized by hairy foliage, usually alternate and simple; flowers are funnel-shaped or tubular. Some of the species contain PYRROLIZIDINE ALKALOIDS.[MeSH]

Cross-References

ID SourceID
PubMed CID6326983
CHEMBL ID109962
CHEBI ID16633
SCHEMBL ID38518
MeSH IDM0026231

Synonyms (18)

Synonym
l-selenocystein
CHEBI:16633 ,
l-selenozystein
selenocysteine
3-selenyl-l-alanine
(2r)-2-amino-3-selanylpropanoic acid
l-alanine, 3-selenyl-
DB02345
selenium cysteine
CHEMBL109962
0ch9049vis ,
unii-0ch9049vis
SCHEMBL38518
selenocysteine [mi]
AKOS025146617
3-seleno-alanine
DTXSID00881371
(r)-2-amino-3-hydroselenopropanoicacid

Research Excerpts

Toxicity

ExcerptReferenceRelevance
" However, several selenium compounds are known to be relatively toxic compounds."( Comparative cytotoxicity of 14 novel selenocysteine se-conjugates in rat renal proximal tubular cells.
Andreadou, I; Commandeur, JN; Nagelkerke, FJ; van de Water, B; Vermeulen, NP, 1996
)
0.29
" Depression of selenium methylation ability resulting from inactivation of methionine adenosyltransferase and Se-methylation via enzymic reaction was also found in mice following repeated oral administration of a toxic dose of Se-Cys."( Mechanisms of selenium methylation and toxicity in mice treated with selenocystine.
Hasegawa, T; Mihara, M; Nakamuro, K; Sayato, Y, 1996
)
0.29
" All of the selenazolidines were much less toxic to the cells than was sodium selenite (IC(50) approximately 17 microM) or the parent selenolamines, L- or D-selenocystine (IC(50) approximately 34 or 39 microM, respectively); OSCA was less toxic than MSCA."( Characteristics of selenazolidine prodrugs of selenocysteine: toxicity and glutathione peroxidase induction in V79 cells.
Cassidy, PB; Li, L; Roberts, JC; Short, MD; Xie, Y, 2003
)
0.32
"Selenium (Se) is an essential trace element with a narrow margin between beneficial and toxic effects."( Elemental selenium at nano size (Nano-Se) as a potential chemopreventive agent with reduced risk of selenium toxicity: comparison with se-methylselenocysteine in mice.
Wang, X; Xu, T; Zhang, J, 2008
)
0.35
" Based on liver pathology seen in female rats in all dose groups, the no observed adverse effect level (NOAEL) for MSC in rats is <0."( Subchronic oral toxicity studies of Se-methylselenocysteine, an organoselenium compound for breast cancer prevention.
Crowell, JA; Johnson, WD; Kapetanovic, I; McCormick, DL; Morrissey, RL, 2008
)
0.35
" This may explain why studies of maternal populations exposed to foods that contain Hg in molar excess of Se, such as shark or pilot whale meats, have found adverse child outcomes, but studies of populations exposed to MeHg by eating Se-rich ocean fish observe improved child IQs instead of harm."( Dietary selenium's protective effects against methylmercury toxicity.
Ralston, NV; Raymond, LJ, 2010
)
0.36
" By comparing the sensitivity to selenomethionine of mutants impaired in the sulfur amino acid pathway, we excluded a toxic effect of Se-adenosylmethionine, Se-adenosylhomocysteine, or of any compound in the methionine salvage pathway."( Trans-sulfuration Pathway Seleno-amino Acids Are Mediators of Selenomethionine Toxicity in Saccharomyces cerevisiae.
Blanquet, S; Dauplais, M; Lazard, M; Plateau, P, 2015
)
0.42
" Since the either adverse or beneficial health effects strongly depend on the ingested Se species, five low molecular weight species were investigated regarding their toxicological effects, cellular bioavailability and species-specific metabolism in human cells."( Differing cytotoxicity and bioavailability of selenite, methylselenocysteine, selenomethionine, selenosugar 1 and trimethylselenonium ion and their underlying metabolic transformations in human cells.
Bornhorst, J; Kuehnelt, D; Marschall, TA; Schwerdtle, T, 2016
)
0.43
" There was no correlation between the potencies of the respective toxic effects and the measured cellular Se concentrations."( Differing cytotoxicity and bioavailability of selenite, methylselenocysteine, selenomethionine, selenosugar 1 and trimethylselenonium ion and their underlying metabolic transformations in human cells.
Bornhorst, J; Kuehnelt, D; Marschall, TA; Schwerdtle, T, 2016
)
0.43
"The essential micronutrient selenium (Se) is required for various systemic functions, but its beneficial range is narrow and overexposure may result in adverse health effects."( Selenium species-dependent toxicity, bioavailability and metabolic transformations in Caenorhabditis elegans.
Aschner, M; Bornhorst, J; Jensen, KB; Kroepfl, N; Kuehnelt, D; Marschall, TA; Rohn, I; Schwerdtle, T; Tuck, S, 2018
)
0.48
"To protect from toxicity at supra-essential doses of selenium, it is important to determine dose levels at which adverse effects occur."( Toxicity of repeated oral intake of organic selenium, inorganic selenium, and selenium nanoparticles: A review.
Hadrup, N; Ravn-Haren, G, 2023
)
0.91

Pharmacokinetics

Methylselenocysteine was tested in patients with chronic lymphocytic leukaemia and a cohort of patients with solid malignancies.

ExcerptReferenceRelevance
" In this study, the effect of methylselenocysteine on pharmacokinetic and pharmacogenetic profiles of genes relevant to CPT-11 metabolic pathway was evaluated to identify possible mechanisms associated with the observed combinational synergy."( Irinotecan pharmacokinetic and pharmacogenomic alterations induced by methylselenocysteine in human head and neck xenograft tumors.
Azrak, RG; Cao, S; Durrani, FA; Li, X; McLeod, HL; Pendyala, L; Rustum, YM; Shannon, WD; Smith, PF; Yu, J, 2005
)
0.33
" In a phase I randomised double-blinded study, the safety, tolerability and pharmacokinetic (PK) profiles of sodium selenite (SS), Se-methylselenocysteine (MSC) and seleno-l-methionine (SLM) were compared in patients with chronic lymphocytic leukaemia and a cohort of patients with solid malignancies."( Comparative Safety and Pharmacokinetic Evaluation of Three Oral Selenium Compounds in Cancer Patients.
Bird, S; Evans, SO; Goodman, HJB; Jacobson, GM; Jameson, MB, 2019
)
0.51

Bioavailability

We also undertook a separate bioavailability study using Se-methylselenocysteine, dimethyl selenoxide, and trimethylselenonium as the starting compounds. We measured the ability of these compounds to restore glutathione peroxidase activity in selenium-depleted animals.

ExcerptReferenceRelevance
" We also undertook a separate bioavailability study using Se-methylselenocysteine, dimethyl selenoxide, and trimethylselenonium as the starting compounds for delivering selenium with one, two, or three methyl groups, and measured the ability of these compounds to restore glutathione peroxidase activity in selenium-depleted animals."( Chemical form of selenium, critical metabolites, and cancer prevention.
Budnick, RM; Ganther, HE; Hayes, C; Ip, C, 1991
)
0.28
" All three compounds were very well absorbed through the gastrointestinal tract."( Chemoprevention of mammary cancer with Se-allylselenocysteine and other selenoamino acids in the rat.
Ganther, HE; Ip, C; Lisk, D; Thompson, HJ; Zhu, Z,
)
0.13
" Bioavailability studies with rats indicated that selenium in ramps was 15-28% more available for regeneration of glutathione peroxidase activity than inorganic selenium as selenite."( Tumorigenesis, metabolism, speciation, bioavailability, and tissue deposition of selenium in selenium-enriched ramps (Allium tricoccum).
Ip, C; Polan, CE; Uden, PC; Welbaum, G; Whanger, PD, 2000
)
0.31
" From this evidence we conclude that HgCl(2): (a) does not inhibit directly SeGPxs, as confirmed on isolated enzymes; (b) does not interfere with the intermediates of the metabolic pathway of selenoprotein synthesis; and (c) decreases the bioavailability of selenium only when ionic complexes can be formed."( Effect of mercury on selenium utilization and selenoperoxidase activity in LNCaP cells.
Bosello, V; Bulato, C; Maiorino, M; Ursini, F, 2007
)
0.34
" The bioavailability and distribution of the two selenium sources in major organs/tissues were compared under exactly identical conditions."( Preferential organ distribution of methylselenol source Se-methylselenocysteine relative to methylseleninic acid.
Ohta, Y; Suzuki, KT; Suzuki, N; Tsuji, Y, 2008
)
0.35
"Determining the effect of selenium (Se) chemical form on uptake, transport, and glutathione peroxidase activity in human intestinal cells is critical to assess Se bioavailability at nutritional doses."( Chemical form of selenium affects its uptake, transport, and glutathione peroxidase activity in the human intestinal Caco-2 cell model.
Cheng, WH; Combs, GF; Jackson, MI; Zeng, H, 2011
)
0.37
" The selenium chemical speciation can strongly affect the bioavailability of this metal and its impact on metabolism, dictating the levels that can be beneficial or detrimental towards an organism."( Characterization of cytosolic glutathione peroxidase and phospholipid-hydroperoxide glutathione peroxidase genes in rainbow trout (Oncorhynchus mykiss) and their modulation by in vitro selenium exposure.
Feldmann, J; Martin, SA; Pacitti, D; Page, MM; Secombes, CJ; Sweetman, J; Wang, T, 2013
)
0.39
" These results of both experiments demonstrate the higher relative bioavailability of SO compared with SS and SY as determined through tissue Se enrichment."( 2-Hydroxy-4-methylselenobutanoic acid induces additional tissue selenium enrichment in broiler chickens compared with other selenium sources.
Briens, M; Geraert, PA; Mercerand, F; Mercier, Y; Rouffineau, F, 2014
)
0.4
" Since the either adverse or beneficial health effects strongly depend on the ingested Se species, five low molecular weight species were investigated regarding their toxicological effects, cellular bioavailability and species-specific metabolism in human cells."( Differing cytotoxicity and bioavailability of selenite, methylselenocysteine, selenomethionine, selenosugar 1 and trimethylselenonium ion and their underlying metabolic transformations in human cells.
Bornhorst, J; Kuehnelt, D; Marschall, TA; Schwerdtle, T, 2016
)
0.43
" While small Se species play a major role in Se metabolism, their toxicological effects, bioavailability and metabolic transformations following elevated uptake are poorly understood."( Selenium species-dependent toxicity, bioavailability and metabolic transformations in Caenorhabditis elegans.
Aschner, M; Bornhorst, J; Jensen, KB; Kroepfl, N; Kuehnelt, D; Marschall, TA; Rohn, I; Schwerdtle, T; Tuck, S, 2018
)
0.48
" We evaluated the effects of administration route and dose on the bioavailability of nine Se compounds found in biota, the so-called bioselenocompounds, such as selenite, selenate, selenocyanate (SeCN), Se-methylselenocysteine (MeSeCys), selenomethionine (SeMet), selenohomolanthionine (SeHLan), selenocystine (SeCys2), 1β-methylseleno-N-acetyl-d-galactosamine (SeSug1), and trimethylselenonium ion (TMSe)."( Effect of administration route and dose on metabolism of nine bioselenocompounds.
Ogra, Y; Suzuki, N; Takahashi, K, 2018
)
0.48
"Selenoneine is likely to pass the intestinal barrier via transcellular, carrier-mediated transport, is highly bioavailable to Caco-2 cells and undergoes metabolic transformations."( Side-Directed Transfer and Presystemic Metabolism of Selenoneine in a Human Intestinal Barrier Model.
Bornhorst, J; Kroepfl, N; Kuehnelt, D; Rohn, I; Schwerdtle, T, 2019
)
0.51
"Selenium is an essential non-metal trace element, and the imbalance in the bioavailability of selenium is associated with many diseases ranking from acute respiratory distress syndrome, myocardial infarction and renal failure (Se overloading) to diseases associated with chronic inflammation like inflammatory bowel diseases, rheumatoid arthritis, and atherosclerosis (Se unload)."( Selenium Donors at the Junction of Inflammatory Diseases.
Alhasan, R; Gaucher, C; Jacob, C; Kharma, A; Leroy, P, 2019
)
0.51
" We describe the uneven distribution of Se and how this affects the bioavailability of this element, which, in turn, profoundly affects the habitat of a region."( Voyage of selenium from environment to life: Beneficial or toxic?
Ballal, A; Banerjee, M; Chakravarty, D; Kalwani, P, 2022
)
0.72

Dosage Studied

The toxicity of 4 compounds (selenate, selenite, methylselenocysteine, and selenocystine) to honeybee adult foragers and larvae was assessed using dose-response bioassays. The mean Se concentration in respired air from sheep administered 6 mg Se/kg BW of different selenocompounds was greatest in sheep dosed Se-methylselenCysteine.

ExcerptRelevanceReference
" As a first step toward the elucidation of the postulated pathway for selenocysteine formation from an L-serine residue esterified to tRNA, we have examined whether an increase in the selC gene dosage allows the demonstration of selenocysteyl-tRNA formation in vivo."( Occurrence in vivo of selenocysteyl-tRNA(SERUCA) in Escherichia coli. Effect of sel mutations.
Böck, A; Leinfelder, W; Stadtman, TC, 1989
)
0.28
" The dose-response was similar for thioredoxin reductase and glutathione peroxidase, but the recovery of glutathione peroxidase activity upon selenium supplementation was faster than with thioredoxin reductase."( Evidence for a functional relevance of the selenocysteine residue in mammalian thioredoxin reductase.
Flohé, L; Marcocci, L; Packer, L, 1997
)
0.3
" More importantly, we found that a short term GGMSC/MSC treatment schedule of 4 weeks immediately after carcinogen dosing was sufficient to provide significant cancer protection, even in the absence of a sustained exposure past the initial 4-week period."( Characterization of the biological activity of gamma-glutamyl-Se-methylselenocysteine: a novel, naturally occurring anticancer agent from garlic.
Block, E; Dong, Y; Ip, C; Lisk, D, 2001
)
0.31
" In this study the absorption, distribution, and elimination kinetics of Se in serum and whole blood of lambs dosed with a single oral dose of (1, 2, 3, or 4 mg Se/kg BW) of sodium selenate or MeSeCys were determined."( Comparative oral dose toxicokinetics of selenium compounds commonly found in selenium accumulator plants.
Davis, TZ; Hall, JO; Panter, KE; Pfister, JA; Stegelmeier, BL; Welch, KD, 2013
)
0.39
" In the present study, the toxicity of 4 compounds (selenate, selenite, methylselenocysteine, and selenocystine) to honeybee adult foragers and larvae was assessed using dose-response bioassays."( Effects of selenium on development, survival, and accumulation in the honeybee (Apis mellifera L.).
Hladun, KR; Kaftanoglu, O; Parker, DR; Tran, KD; Trumble, JT, 2013
)
0.39
" The mean Se concentration in respired air from sheep administered 6 mg Se/kg BW of different selenocompounds was greatest in sheep dosed Se-methylselenocysteine > selenomethionine > sodium selenate > sodium selenite."( Evaluation of the respiratory elimination kinetics of selenate and Se-methylselenocysteine after oral administration in lambs.
Davis, TZ; Green, BT; Hall, JO; Stegelmeier, BL; Welch, KD, 2013
)
0.39
" With high selenium loading, nanoparticles offer a low dosage to restore selenium bioavailability whereas organic selenocompounds can play a role in the modulation of their antioxidant or antiinflammatory activities."( Selenium Donors at the Junction of Inflammatory Diseases.
Alhasan, R; Gaucher, C; Jacob, C; Kharma, A; Leroy, P, 2019
)
0.51
"We identified relevant literature on the repeated dosage of selenium and extracted dose descriptors on reported endpoints, except on genotoxicity/carcinogenicity."( Toxicity of repeated oral intake of organic selenium, inorganic selenium, and selenium nanoparticles: A review.
Hadrup, N; Ravn-Haren, G, 2023
)
0.91
" The future seems bright with the research and clinical possibilities of selenium as a trace element, whose recent experimental clinical treatments have so far involved dosing simply and inexpensively over a set of days, amounts, and time intervals."( Nontoxic Levels of Se-Containing Compounds Increase Survival by Blocking Oxidative and Inflammatory Stresses via Signal Pathways Whereas High Levels of Se Induce Apoptosis.
An, JK; Chung, AS; Churchill, DG, 2023
)
0.91
[information is derived through text-mining from research data collected from National Library of Medicine (NLM), extracted Dec-2023]

Pathways (8)

PathwayProteinsCompounds
Metabolism14961108
Amino acid and derivative metabolism250260
Selenoamino acid metabolism2450
Metabolism of ingested SeMet, Sec, MeSec into H2Se423
Selenocysteine synthesis614
Selenium metabolism selenoproteins02
Selenium metabolism and selenoproteins04
Selenium micronutrient network095

Bioassays (2)

Assay IDTitleYearJournalArticle
AID216730Cytotoxicity activity against V79 cells2003Journal of medicinal chemistry, Jul-17, Volume: 46, Issue:15
Characteristics of selenazolidine prodrugs of selenocysteine: toxicity and glutathione peroxidase induction in V79 cells.
AID75286Glutathione peroxidase activity in V79 cells at 30 uM expressed as fold induction of GPx activity to control value2003Journal of medicinal chemistry, Jul-17, Volume: 46, Issue:15
Characteristics of selenazolidine prodrugs of selenocysteine: toxicity and glutathione peroxidase induction in V79 cells.
[information is prepared from bioassay data collected from National Library of Medicine (NLM), extracted Dec-2023]

Research

Studies (1,325)

TimeframeStudies, This Drug (%)All Drugs %
pre-199063 (4.75)18.7374
1990's196 (14.79)18.2507
2000's426 (32.15)29.6817
2010's471 (35.55)24.3611
2020's169 (12.75)2.80
[information is prepared from research data collected from National Library of Medicine (NLM), extracted Dec-2023]

Study Types

Publication TypeThis drug (%)All Drugs (%)
Trials7 (0.52%)5.53%
Reviews209 (15.47%)6.00%
Case Studies1 (0.07%)4.05%
Observational1 (0.07%)0.25%
Other1,133 (83.86%)84.16%
[information is prepared from research data collected from National Library of Medicine (NLM), extracted Dec-2023]